Knitting machine



March 23, 1965 R. H. LAWSON 3,174,306

KNITTING MACHINE Original Filed July 19, 1956 11 Sheets-Sheet 1INVENTOR. ROBERT H. LAWSON FIG. I.

ATTORNEYS R. H. LAWSON KNITTING MACHINE 7 March 23, 1965 11 Sheets-Sheet2 Original Filed July 19, 1956 8 6 8 8 4 2 v v e 9 A 4 w I1... 6 "r2...B F m 9 o V m 0 8 :H. i I V. Y LHul M M L 4 E I8 6 R 3 6 2 6 O 6 2 6 W 0l A R m 2 O u G F F 8 5 INVENTOR.

ROBERT H. LAWSON ATTORNEYS March 23, 1965 R. H. LAWSON 3,174,306

KNITTING MACHINE Original Filed July 19. 1956 11 Sheets-Sheet 3 VIII 1INVENTOR.

ROBERT H. LAWSON BY ATTORNEYS March 23, 1965 R. H. LAWSON KNITTINGMACHINE 11 Sheets-Sheet 4 Original Filed July 19. 1956 INVENTQR. ROBERTH. LAWSON ATTORNEYS March 23, 1965 R. H. LAWSON 3,174,306

KNITTING MACHINE Original Filed July 19. 1956 ll Sheets-Sheet 5INVENTOR.

ROBERT H. LAWSON ATTOR N EYS FIG. I2.

ll Sheets-Sheet 6 Original Filed July 19. 1956 INVENTOR. ROBERT H.LAWSON BY Ki FIG. ls."

ATTORNEYS March 23, 1965 R. H. LAWSON 3,174,306

KNITTING MACHINE Original Filed July 19, 1956 ll Sheets-Sheet '7 F l G.l4.

FIG. l5.

INVENTOR.

ROBERT H. LAWSON ATTORNEYS March 23,- 1965 Original Filed July 19, 1956R. H. LAWSON KNITTING MACHINE I 11 Sheets-Sheet a- FIG.

INVENTOR. ROBERT H. LAWSON ATTOR N EYS March 23, 1965 R. H. LAWSON 5KNITTING MACHINE Original Filed July 19, 1956 11 Sheets-Sheet 9 FIG. I7.

FIG. l9.

IN VEN TOR.

FIG '& g OBERT H. LAWSON m My ATTOR NEYS March 23, 1965 R. H. LAWSON3,174,306

KNITTING MACHINE Original Filed July 19. 1956 w 11 Sheets-Sheet l0 l (l.5% qz y Y I INVENTOR. F G. 20. BY

March 23, 1965 R. H. LAWSON 3,174,305

KNITTING MACHINE Original Filed July 19. 1956 11 Sheets-Sheet 11INVENTOR.

United States Patent 3,174,365 KNITTENG MAKE Robert H. Lawson,Pawtucket, Rh, assignor to Scott 8: Williams, Incorporated, Laconia,N.H., a corporation of Massachusetts Uriginal application .luly 19,1956, Ser. No. 598,829, now Patent No. 3,629,619, dated Apr. 17, 1962.Divided and this application Dec. 2, 1960, Ser. No. 73,393

Claims. ((l'l. 66-54) This invention relates to knitting machines andhas particular reference to the automatic control of stitch size and isparticularly directed to machines for the knitting of sheer ladieshosiery.

This application is a division of my copending application Serial No.598,829, filed July 19, 1956, and issued April 17, 1962, as Patent No.3,029,619.

Difliculties are experienced in the knitting of sheer ladies hosiely, inparticular, in that, due to variations in yarn and in the tension ofyarn fed to the needles, stitches of varying length or size areproduced. The variations in size of individual loops are minute, but dueto the fact that a ladys stocking contains a very large number ofcourses, the minute variations of individual stitch lengths arecumulative to the end that successive stockings produced on the samemachine and seemingly under identical conditions will vary greatly withthe result that, after finishing, the stockings must be carefully sortedinto pairs of approximately equal lengths. Furthermore, while theintention may be to produce stockings of particular lengths, there maybe produced undesired numbers of stockings varying so far from thedesired lengths that for a mill to fill an order an excessive number ofstockings may have to be produced, the stockings of undesired lengthsbeing then retained in hopes of filling an order requiringtheir lengths.

Furthermore, the variations in stitch lengths may occur in such fashionthat groups of courses having stitches of abnormal lengths may beinterposed between groups of courses having stitches of normal lengths,and the result in such cases will be the appearance of horizontalshadowy streaks which may make the stockings unacceptable.

Further, stitches may vary in size sufiiciently to produce abnormalreductions or increases in stocking circumference causing the stockingto be locally too tight or too loose when worn.

The variations indicated above as of objectionable type are not to beunderstood as those which are intentionaliy provided for the shaping ofstockings. it is common practice to change stitch size in a smoothlycontinuous fashion in shaping ladies hosiery from the calf portions intothe ankle portions. Such variations are definitely programmed by thecontrolling mechanism of the knitting machine. The objectionablevariations here under discussion are those which normally occur beyondintentional control.

In the US. patent to Vernon Thomas Stack, No. 2,685,786, dated August10, 1954, there is disclosed mechanism in a knitting machine for theautomatic control of stitch lengths having as its object the preventionof shadow streaks or rings, the production of proper stocking diameters,and the attainment of stocking of desired overall lengths. In accordancewith the mechanism of said Stack patent, there is provided detection ofvariations of lengths of stitches as the stitches are being formed, withprovision for correction of stitch lengths so as to avoid the cumulativeoccurrence of stitches in large groups of successive courses which wouldlead to the objectionable results above discussed. In brief, inaccordance with the said patent, the positions of sinkers are detectedto give rise to signals indicative of variations of stitch lengths fromnormal, and the signals thus produced control through reversibleelectric motor means devices which change the relative positions of thestitch drawing needle cams and the ledges of sinkers over which thestitches are drawn. The mechanism so shown allows for the intentionalvariations of stitch length incidental to the usual fashioning orshaping procedure, but prevents deviations from the locally normalstitch lengths in such fashion that cumulative errors do not occur.

It is the general object of the present invention to improve themechanism of the general type disclosed in said Stack patent for thepurpose of control of the stitch lengths.

In accordance with the present invention, the control is pneumaticrather than electrical. The pneumatic control 1 have provided producessmooth and reliable operations, avoiding the possibilities of failure ofelectrical elements and the complexities involved in electrical control.Furthermore, from a practical standpoint, a single type of pneumaticmechanism may be provided for all localities, domestic and foreignsince, except for a driving motor for the air supply, it is independentof the local power supply which may vary from place to place in voltageand frequency and would necessitate the provision of wholly differentelectrical systems for various places. Due to the relatively slow andsmooth action of the pneumatic control provided, sudden variations institch lengths or sizes are prevented, and this is highly desirablesince any sudden change in stitch length will be noticeable as a streakor mark in the fabric. Desirably the corrective actions should be slowso that in successive courses, even though a corrective action is takingplace, there will be no change in stitch length which will be apparentto the eye.

The foregoing and other objects particularly relating to details willbecome apparent from the following decription read in conjunction withthe accompanying drawings in which:

FIGURE 1 is an elevation, partly in section, showing in particularcertain conventional elements of the type of knitting machine to whichthe invention may be applied;

FIGURE 2 is a diagram illustrating the connections of a preferred typeof pneumatic system;

FIGURE 3 is a plan view of a suitable type of pneumatic relay utilizedin carrying out the invention;

FIGURE 4 is a vertical section taken on the plane indicated at 4-4 inFIGURE 3;

FZGURE 5 is an enlarged vertical section taken on the broken surfaceindicated at 55 in FIGURE 3;

FlGURE 6 is a vertical section taken on the plane indicated at 6-6 inFIGURE 3;

FIGURE 7 is a fragmentary plan view showing in particular the detectingmeans for abnormal stitch length;

FIGURE 8 is a perspective view showing the details of the detector;

FIGURE 9 is a further perspective view showing details of the detector;

FIGURE 10 is a fragmentary elevation showing certain elementsparticularly involved in the fashioning control of the stockingformation;

FIGURES 11 and 12 are fragmentary elevations, partly in section, showingcertain details of the controlling mechanism;

FIGURE 13 is a fragmentary plan view of the stitch control arrangementinvolving control of the penetration of the sinkers between the needles;

FIGURE 14 is a fragmentary elevation, partly in section, of a portion ofthe mechanism shown in FIGURE 13;

FIGURE is a fragmentary elevation of a portion of the mechanism shown inFIGURE 13;

FIGURE 16 is a fragmentary elevation illustrating a valve controlprovided in the machine;

FIGURE 17 is a diagrammatic elevation showing certain air controlsinvolved in the machine;

FIGURE 18 is a fragmentary elevation showing valve operating meanscontrolled in accordance with operation of the machine;

FIGURE 19 is a sectional view of the same;

FIGURE 20 is a sectional view showing, in particular, a type of sinkerwhich may be used for stitch control;

FIGURE 21 is a fragmentary plan view showing the stitch controlarrangement involving control of the positioning of sinkers of the typeshown in FIGURE 20;

FIGURE 22 is an elevation, partly in section, of the mechanism shown inFIGURE 21;

FIGURE 23 is a fragmentary elevation showing mechanism for securingcontrol of stitch length by shift of position of the sinker cap; and

FIGURE 24 is an elevation looking at the right of FIGURE 23.

As noted above, the invention is particularly applicable to knittingmachines for the production of ladies sheer hosiery wherein the matterof stitch control is particularly important, though it will be evidentthat the invention is more broadly applicable to knitting machinesgenerally.

For purposes of illustration, the invention will be described as appliedto a machine of the type arranged to knit ladies sheer-hosiery, themachine which will specifically be referred to being of the typedisclosed in our US. Patents No. 2,625,026, dated January 13, 1953, andNo. 2,709,352, dated May 31, 1955. Such a machine, certain parts ofwhich are indicated in FIGURE 1, comprises a slotted needle cylinder 2associated with which is the non-rotating but axially movable cylinderraising tube 4 which is vertically moved for the purpose of control ofstitch length. Heretofore such a tube has been raised intermittently tocontrol changes in stitch length as between major parts of the completestocking and in particular where yarn changes have been effected, andalso for the gradual control of stitch length to produce properfashioning of a stocking from the calf into the ankle. The adjustment ofstitch length in this fashion is well known and is the result ofchanging the vertical height relationship between the ledges of thesinkers 8, over which the stitches are drawn by the needles 6, withrespect to the level of the cams (not shown) which are at a generallyfixed height and control the needle movements.

The machine is illustrated as comprising also the dial 10 which carriestransfer elements 12 for the production of turned welts. Also indicatedis a grab takeup 14 of the typedescribed in detail in my prior patentand application, which takeup makes possible the maintenance of propertension during the knitting of stockings which are individually andseparately knit, each being started on bare needles. In the remainingportion of the description herein there will be referred to only thoseelements which are intimately concerned with the invention hereininvolved, it being understood that the knitting machine is otherwise ofconventional type arranged to knit complete stockings including heelsand toes.

Reference may first be made to a pneumatic relay shown in FIGURES 3 to6, inclusive, two of such relays being used in the various pneumaticcontrol systems hereinafter referred to. The relay comprises a multiparthousing 16 which provides various air connections and chambers andcontains operating valve means. The housing provides an air supplypassage 18 which communicates through a passage 20 with a chamber 22.The passage 18 also communicates through a restricted orifice 24 with apassage 26 which at one end 28 is arranged to be connected to a nozzleas will be hereafter described and at its other end through extension'38 to a chamber 32 a portion of the lower wall of which is provided bya flexible diaphragm 34. The diaphragm 34 carries a conical valve member36 which cooperates with a conical seat portion 38 of a passage 39 whichconnects the space 40 beneath the diaphragm 34 with the chamber 22. Thevalve member 36 is provided with a stem 42 of smaller diameter than thepassage 39 which is arranged to engage and press downwardly a ball 44which acts as a valve member to seat in the lower end of the passage 39to close the passage, the ball 44 being urged upwardly by a light leafspring 46. Passages 48 and 5t furnish communication between the space 40and the atmosphere. Communicating with, and extending laterally from thepassage 39 is a passage 52 which, through its extensions 54 and 56provides a controlled air outlet.

As will hereafter appear, a nozzle connected to the end 28 of passage 26is controlled by a movable baffle which, by impeding the escape of airto the atmosphere produces, in conjunction with the fixed orifice 24, avariable pressure condition in the connection 30 and the chamber 32. Asthe pressure in this chamber increases, the valve member 36 is moved bydiaphragm 34 toward a position closing the upper end of passage 39 andunseating the ball 44 from the lower end of this passage so thatcommunication is afiorded between the chamber 22, which received thesupply air, and the air outlet at 56. On the other hand, if the flow ofair from 28 is relatively unimpeded by movement of the baflie away fromthe corresponding nozzle, the pressure in chamber 32 is reduced due tothe resistance to How imposed by the orifice at 24, and the diaphragm 34is raised by the action of spring 46 which seats the ball 44 and raisesthe valve member 36 so that the passage 39 is put in communication withthe atmosphere through the space 40 and the venting passages 48 and 50.The result is that, when the valve member 36 is in fully openedposition, .the outlet 56 is connected to the atmosphere. In this fashiona relay action is secured providing either the supply pressure oratmospheric pressure at the outlet 56 in dependence upon-the position ofa bafiie associated with a nozzle connected to the end 28 of passage 26.Relays of this type are well known in indutstrial uses, and details ofits operation need not be described. It will sufiice for the presentinstance to state that the relay is capable of providing a very largepressure difference under control of minute movements of the bafliereferred to.

FIGURE 2 shows a typical diagram of a pneumatic system incorporatingrelays of the type just described which may be used forstitch controlpurposes in the various arrangements hereafter discussed. Air issupplied at suitable high pressure at 58 through a filter 60 to areducing valve 62 adjustable by means of a knob 61 so as to provide thedesired input pressure to the relays 64 and 66, through a valve 63which, as shown in FIGURE 16 is controlled through an arm 65 which isconnected by link 67 to an extension of the conventional lever 69activated by the pattern chain 71 to enable the usual pawl 73 to engagethe drum ratchet Wheel 75. Reducing valves are well known which willmaintain substantially constant output pressure for large fluctuationsof input pressure and such valves are desirably used in a mill where thesupply pressure may fluctuate considerably in view of intermittent usesof large amounts of air for other purposes associated with a number ofknitting machines. The control connections 68 and for the relays,corresponding to connections to the passage 26 at 28 of the relayalready described, terminate in nozzles 184 and 186 with which cooperatebaffles 168 and 170 arranged to control the outflow of air from thenozzles. While a pair of baffles are shown herein it has been found thatequally satisfactory results may be obtained by one baflle operatingbetween directly opposed nozzles. However, the principle of control ofthe double baffles shown herein applies to control of the single.bafiie. The relay 64 is shown as awasos having its output connected at89 to an accumulator 32 in the form of a tank containing oil. Theoil-containing space of this accumulator 82 is connected to one end of acylinder 84 through a connection 36 controlled by an adjustable valve88. The cylinder 84 contains a piston 92 to which is secured a pistonrod 94 from which mechanical power is derived. The output of the relay66 is connected at 5 through a filter 91 to the side of the pistonopposite that supplied through connection 85. Filter 91 is so arrangedthat any liquid leaking past piston 92 will be prevented from enteringrelay 66. Considering specifically the arrangement shown in FIGURE 2(which may be replaced by numerous pneumatic arrangements known to theant), if the bathe 168 approaches more closely to the nozzle 134,pressure in the relay 64 will be built up above the diaphragm 34 thereofproviding pressure air from the supply through the connection 80 todisplace oil from the accumulator 82 to drive the piston 92 downwardly.The valve 83 is desirable since, by partial closure of this valve, theoil flow, due to its viscosity, may be slowed down to provide a smoothslow movement of the piston 92 rather than a rapid movement. Slowmovement is desirable not only to prevent hunting but further in thecase of stitch length adjustment since a rapid adjustment of stitchlength might result in such a sharp change in the stitches that avisible shadow ring or other marking might result. Desirably the changeis a gradual one so that substantial change will not occur except over aknitting period of several courses. As will be evident, if the baffle17% is moved toward its nozzle and the baflie 16S simultaneously movedaway from its nozzle a reverse action will occur involving upwardmovement of the piston 92 and reverse flow of oil through connection 86and valve 88 from the cylinder to the accumulator. As will appearhereafter the baffles 165 and 170 are moved oppositely with respect totheir nozzles so that reverse movements of the piston 92 correspondinglyoccur to effect corrective actions in one of the fashions which will bedescribed. It may be noted that the pneumatic control may be of one ofthe more elaborate types well known in the process control art toachieve fine control with avoidance of hunting, though the simplecontrol described has been found highly satisfactory for stitch controlpurposes.

It is desirable in machines of the type herein disclosed to shut or? themain air supply when the machine stops due to the operation of the stopmotion or for other cause such as failure of the main power supply ormanual stopping of said machine. Heretofore, air used in conjunctionwith a grab take-up has been shut oti, when the machine was manuallystopped, to prevent waste of air.

In the present instance, where the stitch size is servo controlledthrough a detector cam 150, the control action or which is hereafterdescribed, stopping of the machine with the air on may cause the piston92 to travel to its extreme in one direction or the other depending uponwhich of the relays 64 and 66 happens to be activated when the machinestops, if the comparatively simple system herein described is used. Anextreme stitch such as would be obtained when the piston 92 goes to oneextreme or the other in its cylinder 84 would cause ditficulty inrestarting the machine due to the stitch being too tight or loose and ofcourse would in any case result in loss of the stocking.

One example of a control for shutting oif the air when the machine stopsfor any reason is shown in FIGURES 17, 13 and 19. This control consistsof housings 590 and 592 held together by screws 504. A shaft 566carrying a bladed rotor 598 passes thru bearings 510 and 512respectively in housings 500 and 5192. These bearings carry seals suchas may be provided by 0 rings to prevent lubricant inside housings S00and 562 from passing out between rotating shaft and bearings 519 and512. Shaft 506 also carries fastened thereto a gear 514 which mesheswith the bull gear 51s with which ma chines of the type here disclosedare equipped, being used to drive a quadrant gear (not shown) through aconnecting rod (not shown) to oscillate the cylinder during the makingof heels and toes. Gear 516 always travels in one direction regardlessof whether the needles are revolving or reciprocating.

Bladed rotor 55% is made integral with shaft 506 as by brazing and assaid shaft 556 is caused to rotate the rotor 508 revolves insidehousings 500 and 502. Housings 5% and 592 are provided with cavitiesseparated by walls and the latter approach the blades of rotor 508,being separated therefrom by a very small clearance being measured inone or two thousandths of an inch. Housings 5% and 502 with the rotor508 therein are completely tilled with a grease that will substantiallymaintain its density over a wide heat range, for example, a siliconegrease. The movement of the grease caused by the angular blades on rotor508 from cavities in one of the housings 500 and 502 to the cavities inthe other housing causes a torque to be applied to said housings whichvaries as the speed with which rotor 5% is turned.

This device has been so designed and the gear ratio between 516 and 514-is such that when the machine is run at its slowest normal speedsufficient torque is built up in housings 5th) and 5:32 to cause them torevolve clockwise as seen in FIGURE 18 against the tension applied by aspring 513 thus opening a valve 52%) through a link 522. Spring 518 actsnormally to close valve 520 immediately upon stopping of the machinewith consequent loss of torque to housings Silt) and 502. Spring 518through link 522 revolves said housings 50% and 5432 anti-clockwise(FIGURE 18) lifting the lever of valve 524 and closing the valve.

Air is suppled to valve 52% immediately following its passage throughfilter and before entering an air controlled pilot operated valve 524located between filter 60 and reducing valve 62. Thus air is availableto valve 529 regardless of whether valve 524 is open or closed but airis available to the grab take-up and the pneumatic stitch control onlywhen valve 524 is open. Running of the machine causes housings 5% and592 to revolve clockwise as explained above overcoming the tension inspring 518 and opening valve 520 thus supplying air to the pilot side ofvalve 524 causing the opening of said valve 524 and the consequentsupplying of air to various parts of the machine as required.Stopping'of the machine or even abnormal slowing down of the machinereleases the torque built up in housings 569 and 502 allowing spring 518to returnthem to a position where thru connection 522 they will causevalve 529 to close, which in turn shuts off main valve 524.

Changing the density of grease in housings 5% and 562, changing therelative diameters of these housings and rotor S98 and also changing thetenson in spring 518 will cause opening and closing of valve 520 tooccur at different speeds of the knitting machine as may be desired.

The physical arrangement of the accumulator S2 and cylinder 84- andtheir associated parts, diagrammed in FIGURE 2, is shown in FIGURE 17,the accumulator and cylinder being secured to a leg of the knittingmachine as illustrated therein. The piston rod 94 has connected to it aplate 96 which through a link 98 is connected to operate the deviceschanging stitch size by control of the sinker movements.

The shaft 142 of the main pattern drum of the machine, which isconventional and not shown, has secured to it, by location on itsdriving gear, a cam 144 which is arranged to operate on a plunger 146which is connected to a link 148. This serves for activation ordeactivation of the pneumatic controlling means as will appearhereafter.

Reference is now made to FIGURES 7, 8 and 9 which illustrate the stitchsensing mechanism, tlus mechanism also being illustrated in an explodedview comprising FIGURE 9A of Patent 3,029,619 previously referred tohereinabove.

A detector cam 150 which rides on the butts of sinkers 8 is pivoted at152 in a slot in the sinker cap. Engageable with this detector cam isthe depending finger 154 of a lever 156 which is pivoted on a pin 158fixed in a slide 160 which is slidable toward and from the axis of theneedle cylinder in a fixed bracket 162.. Two other levers 164 and 166are also mounted to pivot on the pin 158 and carry respectively thebattles 168 and 170. Lever 156 is provided with a lateral extension 172in which is threaded an adjustable screw 174 the lower end of which isarranged to bear upon the bafiie 178. A spring 176 between the bafileand screw urge them into engagement. An extension 178 of lever 164 hasthreaded therein an adjustable screw 180 which bears upon the end oflever 156. A spring 182 reacting between the screw 188 and a fixedelement serves normally to maintain the engagement between screw 180 andthe lever 156. The bafiles 168 and 170 cooperate, respectively, with thenozzles 184 and 186 as illustrated in FIGURE 2, and opening,respectively upwardly and downwardly. As will be evident from the priordescription of FIGURE 2, when the battle 176 closes off the flow of airfrom nozzle 186 there will be built up pressure beneath the piston 92 toeffect rise of the piston. On the other hand, if bafile 168 closesnozzle 184 the piston will be moved downwardly.

' A wedge 188 is arranged for vertical movement in the bracket 162 andis moved by a heavy Bowden wire 1% which extends through a sheath 192and is connected at its other end to a lever 194. The slide 169 isprovided at its outer end with a plate 196 in which is threaded anadjustable screw 198 which rides on the wedge 188. A spring 200 urgesthe slide 160 toward the axis of the needle cylinder. A lever 202 whichis pivoted to the frame at 204 is connected at 206 to an adjustableextension 208 of the link 148. The outer end of the lever 202 engagesthe plate 196 so that, as link 148 is raised through the action of cam144 the slide 160 is moved outwardly from the needle cylinder. Securedto the upper end of link 148 is a block 210 which is provided with awire arm 212 having a portion 214 underlying the baflle 168. Thearrangement is such that as the link 148 is raised the baflle 168 israised away from its nozzle 184.

- The lever 194 to which reference has alreday been made is pivoted at216 to a bracket 218 and is provided with three aligned adjustablescrews 220 only one or" which appears in FIGURE 10. These screws arerespectively adapted to be engaged by cams 222, 224 and 226 carried bythe fashioning drum 138 which is journalled on the shaft 142 as shown inFIGURE 11. The fashioning drum is provided with ratchet teeth 228extending approximately two-thirds of the way about its circumferenceand arranged to be acted upon in usual fashion by a pawl 229 whichreciprocates during operation of the machine. An adjustable screw 230 ismounted in the lever 4 and is arranged to limit its counterclockwisemovement under the action of spring 234 by abutment with lateralextension 232 of the bracket 218.- The cam 222 is contacted by lip 238to advance drum 138 where teeth 228 are omitted. Said lip 238 isprovided on a plate 239 secured to the shaft 142. A spring brake 240holds the fashioning drum 138 in position against accidentaldisplacement and also serves to restrain overrun of this drum.

FIGURES 13, 14 and 15 show the arrangement for changing stitch size bycontrol of the sinker movements. The sinker cap 242 is provided with asinker butt detector cam 150 pivoted at 152 and arranged to act upon thelever 248.

The center sinker cam 250 is of generally conventional shape but in thiscase is pivoted at 252. The rundown castofi' sinker cam 254 is pivotedat 256. This cam also 8 is substantially in its shape conventional,though the ad jacent portions of the cams 250 and 254 are modified sothat during simultaneous movements they will not pinch the sinker butts.Pins 258 and 260, respectively carried by the cams 250 and 254, extendupwardly through slots in the sinker cap and are pivoted in openings ina plate 262 which is also pivoted at 256, being provided with anextension 264 acted upon by a spring 266 serving to urge the plate 262counterclockwise. A bracket 268 carried by the sinker cap is threaded toreceive an adjustable stop screw 27% which bears against the outside ofearn 254 to limit its outward movements. A bracket secured to the latchring support post 272 is provided with guiide elements 274 for a slide276 which is provided with an enlarged T-shaped head 278 limiting itsinward movement. A spring 289 urges the slide 276 outwardly. A lever 282pivoted at 284 and operable by a thrust rod 286 acted upon by cams onthe main cam drum, is provided with a pad 288 urged outwardly of itsupper end by a strong spring 290 capable of overcoming the tension ofspring 280. Pivoted at 292 on slide 276 is a lever 294 provided with ahorizontal arm engageable by the link 98, previously described. At itsupper end the lever 294 is provided with an eccentric cam 298"engaging,when in operative position, the plate 262 and arranged to rock it aboutits pivot 256 against the action of spring 266.

Depending upon the connections of the elements just described operationsmay be effected in various diiferent Ways for control of stitches byproducing greater or less inward movements of the sinkers under theaction of cam 254. It may be noted that cam 250 is movable with cam 254to provide control against overrun of the sinkers while still avoidingpinching of the sinker butts. The stitch controlling action, however, isdependent upon the position or" the rundown castolf sinker cam 254. Thatis, the castofi movements of the sinkers are controlled for correctingthe size of the stitches.

During the knitting of portion of a stocking in which no control iseffected, the thrust rod 286 is in lowered position so that the spring280 is free to retract the slide 276 and with it the cam 298, freeingthe plate 262. It.

may be noted that under these conditions there is no possible conflictwith reciprocatory movements of the latch ring during the knitting ofheels and toes. The detecting means and the pneumatic control means maybe completely deactivated by the withdrawal of the slide carrying thelever 248 along with deactivation of the bafile corresponding to 168.When stitch control is desired, thrust rod 286 is moved upwardly toforce the slide 276 to its extreme inner position, thereby locating thecam 298 in position for operation. Control of a wedge such as 188 underthe action of pattern devices of the type already described thencontrols the size of stitches detected by the cam 158 following thesinkers 8 and eifecting movement through the piston of the lever 294 andcam 298. If longer stitches are called for, the action is to drop lever294 so as to move inwardly cam 254 and thereby cause the sinkers to drawlonger stitches as they are formed. It may be noted that the movementsof the cam 254 by reason of its pivotal mounting are such as to move thesinkers inwardly slightly earlier than usual and also slightly furtherthan usual when the cam 254 is moved inwardly. By difierent' mounting ofthe cam either of these actions alone may be used for the control ofstitch size. If earlier inward movement of the sinkers is depended uponfor control, the sinker cap may be moved by a mechanism of obvious typecontrolled through a thrust rod corresponding to 286. Conversely ifstitches that are too large are being formed, the operation is such asto permit outward movement of cam 254 under the action of spring 266thereby effecting the formation of smaller stitches.

' During the makeup. at the start of the stocking the height of theneedle cylinder is controlled in the usual manner from the main cam drumof the machine. At this time the piston 92 will be in the positionresulting from the formation of the ankle of a previous stocking, andwill he, therefore, in a lowered position corresponding to automaticcontrol of tight stitches. The follower 146 is at this time raised byearn 144 and, consequently, the slide 16% is in retracted position withthe result that baffle 170 is clear of the nozzle 186. At the same timethe end 214 of wire 212 holds the battle 168 raised from nozzle 184. Theair system is accordingly deactivated, so that the piston remains asstated. If desired, the air system may also be deactivated by closure ofan air valve from the main cam drum, though such deactivation wouldserve no purpose except to prevent waste of air through the nozzles.

During the fashioning of the ankle of the preceding stocking the pawl229 will have advanced the ratchet 228 until, following the engagementof the trailing tooth, it will be riding idly upon the portion of thedrum 138 which has no teeth. During the formation of the heel, foot, andtoe of the preceding stocking and the initial part of the makeup of thenew stocking the shaft 142 will have stepped about, but will not havecaused lip 233 to engage the portion 236 of cam 222. During the lastdrum move involved in the makeup, the shaft 142 will have a step so that238 will engage 236 to move the cam 222 beneath the corresponding screw22% to position the lever 194 and the wedge 18% properly for the makingof welt stitches.

esirably at this same time the usual cams are moved to effect movementof the needle cylinder to a height which would correspond to theproduction of welt stitches slightly tighter than desired, and also toraise thrust rod 286 so that the stitch size controlling means will berendered operative.

Also at this time the rod 1.46 is released by the cam 144. The result isthat bafiie 163 is released and and the slide 16% moves inwardly toengage follower screw 198 with the wedge 188 occupying now a positioncorresponding to the production of proper size welt stitches. The sinkerdetector cam will now in a position slightly outwardly of that desiredin view of the formation of welt stitches tighter than desired, andconsequently lever 156 will be rocked counterclockwise to engage baflle1'79 with nozzle 186. The piston will accordingly be caused to rise asalready described to move the link 93 in the direction to eilect aproper positioning of earns and 254-. As slackening of stitches results,the sinkers are moved inwardly under the action of detector cam 50through the action of spring 182, effecting removal of bafiie 176 fromnozzle 186, thereby arresting the piston movement. Control in thisfashion is typically attained within one or two courses after thepneumatic stitch control device is activated, though the rapidity ofaction of this control is adjustable through control of valve 83.

During the knitting of the welt automatic stitch length controlcontinues. If the stitches become too tight, the detector cam 15% ismoved outwardly by the sinkers resulting in closure of nozzle 18% bybaffle 17% and slight readjustment of the cams 256 and 254 by theraising of lever 294. On the other hand, if the stitches become tooloose, the follower cam 15% moves inwardly with the result that nozzle184 is closed by baffle 168 resulting in slight downward adjustment ofthe lever 294. Desirably, the automatic adjustment is relatively slow,so that there is no radical change in size of the stitches such as wouldproduce an appearance of rings in the fabric. It may be noted that thestitch adjustment is not an adjustment of abnormal stitches alreadydrawn, but rather is in the nature of a compensating adjustment ofsubsequently formed stitches both to balance the abnormal stitches andsecure stitches of more proper length. This action of compensating forstitches of abnormal size is important throughout the formation of thecircular knit parts of a stocking, and particularly the leg, to be sureof proper overall size of the stockings produced.

Continuing the description of the operation, following the transfer ofthe welt the drum 138 is advanced by engagement of lip 233 with cam end236 to release cam 2-22 from its follower screw and to bring earn 224into engagement with a second one of the screws 22% to position thewedge 188 properly for the formation of shadow welt stitches. The actionis, of course, to reposition the slide res so that the automatic controlmay be etfect'ed from a different predetermined value of stitch length.Automatic control would then take place as before, and the screw 22%which follows cam 224 may be adjusted to secure the desired stitchlength. It may be here remarked that adjustment of screw 1% is primarilyto effect a common adjustment of all stitches while the relativepositions of the screws 22% effect relative adjustment to the stitchesin the different areas of the stocking.

At the beginning of formation of the leg actions similar to those justdescribed take place, the drum 138 being again advanced so that thethird screw 226 engages the initial portion of cam 226 to set the wedge188 to proper position for the additional leg stitches. Again the needlecylinder is lowered by means of the usual cam drum to etfect quickchange of stitch size, which is followed by automatic readjustment ofthe piston 92 to accomplish, through link 98, automatic control of thestitches in accordance with the position of the wedge 188. As discussedin greater detail hereafter, the primary control over fashioning of theleg may be effected by the usual means acting to raise and lower theneedle cylinder or such fashioning may be effected solely throughadjustment of wedge 188. Thus the automatic control is called uponmerely to effect such minor adjustments as are required in view ofvariations in yarn tensions, or other matters which may elfect stitchsize.

Through the events already described the drum 138 has not been advancedsufliciently to permit engagement of pawl 229 with the leading tooth ofthe ratchet 228. At the time fashioning of the leg is to start, lip 238will advance the end 236 of cam 222 to an extent bringing the leadingratchet tooth in position to be engaged by pawl 229. Thereafter, drum138 is advanced through an arc corresponding to one tooth, desirablyonce for each four revolutions of the needle :cylinder. The followerscrew of lever 194 which follows earn 226 then rides down this camproducing step by step small incremental upward movements of wedge 1S8thereby causing slide 160 to be retracted from the axis of the needlecylinder. Thus there is produced progressive tightening of the stitchesas determined by cam 226, the automatic control, of course, functioningmso to maintain the stitches of the desired size, on the average,despite other factors such as changes in yarn tensions, temperaturechanges, or the like. The automatic fashioning control action justdescribed is terminated when the screw 230 engages the portion 232 ofbracket 218. The adjustment of screw 230 accordingly controls theminimum stitch size involved in the production of the ankle and also thefoot.

At the start of the heel the automatic control is rendered inopenativeby the action of cam 144 which raises rod 146 and link 148 to deactivatethe control by locating its parts in the positions first described inthis discussion of operation. Also, thrust rod 286 is lowered to renderthe automatic stitch size controlling means inoperative as heretoforedescribed. As the result of knitting tight stitches in the ankle, thelever 122 will occupy a low position and will remain in this positiondue to the deactivation of the control. Accordingly the needle cylindermay be naised by the usual cams on the main cam drum to the properposition for the formation of desired heel stitches.

At the completion of the heel the automatic control may be resumed ornot as desired. The arrangement specifically shown for the cam 144 inFIGURE 12 assurnes that control is to be renewed during the formation ofthe foot of the stocking. The depression in the cam 144 permits thecontrol to be reactivated in passing from the heel to the foot.Generally, to provide avoid- 1 l ance of a sharp line of demarkation ofstitches across the instep the wedge 188 will desirably continue in theposition last occupied prior to the formation of the heel, i.e., theposition in which screw 230 engages step 232. However, while this may bethe initial position it will be obvious that fashioning may occurthrough the foot, involving widening thereof, by continuation of controlunder the action of cam 226 serving to rock the lever 194 so as to exertdownward movement on the wire 190. Then when the knitting of the tee isstarted another high section of the cam 144 operates to deactivate theautomatic control.

For automatic control of the foot stitches it is desirable to controlthe valve 63 from the pawl holder 69 as shown in FIGURE 16, the valveshutting ofi the air to the system from a time prior to completion ofthe heel until the pawl holder rides ofi the link of the chain 71 twocourses after going out of the heel. Otherwise, the tight heel stitcheswould operate cam 150 so as to call for a looser stitch and the piston92 would move far enough to make a loose course at the start of thefoot. Accord ingly, the control is held inoperative after plunger 146drops into depression 145 until foot stitches are detected, whereuponthe automatic control continues, being initiated by reopening of valve63. The drum 138 continues to step around untilthe last tooth of theratchet 228 has been advanced. Thereupon the drum comes to rest, to benext moved by lip 233 as previously described.

Although the automatic control may be used for fashioning, preferablyits action is confined essentially to control of the stitch size againsta normal magnitude by having the vertical relation between the needleand sinker controlled in theusual Way from the main cam drum both forstitch changes in different parts of the stocking and also forfashioning, the automatic control only taking care of variations causedby the yarn, temperature change, etc. In transitions from the welt tothe shadow welt or from the shadow welt to the leg the needle cylindermay be rapidly moved to change the stitch size and at the same [time theWedge 188 may also be rapidly moved. However, the control will thenordinarily be temporarily rendered ineffective since, as previouslydiscussed, it is desirable that the automatic control should take placeslowly. Nevertheless, quick transitions in stitch size will occur andafter one or more revolutions of the needle cylinder the automaticcontrol will become operative to take care of corrections of minorvariations due to changes in yarn tension and other causes, the controlbeing, however, about the desired stitch length determined primarily bythe cylinder position.

In similar fashion, the fashioning in the leg of the stocking ispreferably primarily eifected by reason of the adjustment of needlecylinder position. While the wedge 188 must be moved to correspond tothefashioning desired, what has just been stated means that the sinkersneed have very little variations in their position, only suflicient toetfect minor corrections. On the other hand, if there is dependence uponthem for complete fashioning, then they will have correspondingly largevariations in their paths with necessity for substantial movements ofcam 254 throughout the full range of operation.

A device for resetting the piston 92 will be described with reference toFIGURE 17. At the completion of the stocking piston 92 will be in itslowest position, where it was placed to make the tight stitch requiredin the ankle and foot. preferably during the making of the loopers wastecourses, master switch 526 (a normally open switch) is closed by a cam528 located on the main drum. This will cause current to flow through anormally closed switch 492' causing solenoid operated valve 530 to opensupplying air to the bottom of cylinder 84. Air thus supplied will causepiston 92 to rise. A cam 476' fastened to slide 96 will cause switch 492to .open when piston 92 has reached the desired height, deenergizingsolenoid During the completion of the toe, or

12 valve 530 and shutting off the air to the base of cylinder 84 andleaving piston 92 at the height desired for starting the welt. The nextdrum move will open switch 526 so solenoid valve 530 will not operateuntil the end of the next stocking is reached.

The stitch control may involve the use of sinkers having sloping ledgesover which the stitches are drawn by the needles, with variations ofsinker positions at the time the stitches are drawn. Such an arrangementis illustrated in FIGURES 20, 21 and 22. The type of sinker which may beused is illustrated at 8' in FIGURE 20 and is shown as comprising asloping ledge portion 300 associated with the horizontal ledge portion301 adjacent to the sinker throat. Various sinker constructions may beused with the sloping ledge. 300 at greater or less angle and eitherassociated with a horizontal ledge 301 or extending in sloping fashionto the sinker throat. If the automatic adjustments effected by radialsinker position are to be for minor corrections of stitch length aslight slope only is required. However, if the sinker positions aredepended upon for major changes in stitch lengths then the slope may bequite steep.

FIGURES 21 and 22 illustrate a desirable .type of mechanism forcontrolling the sinker positions. The sinker cap is indicated at 302 andsupports the castofii cam 304 which, in this case may be fixed inposition. The center cam desirably has two parts, the first, indi' catedat 306, being pivoted at 308 and the second indicated at 310 being fixedand secured at the points 312 and 314. These two cams overlap in theregion 316 to present, for all positions of adjustment of cam 306 asmooth cam arrangement for operating on the sinker butts during eitherdirection of movement. The spring band 317 urges the sinkers inwardly tocause them to follow the cam 306. The cam 306 at its free end isconnected through a pin 31% to a plate 320 which is pivoted at 321 andis limited in its clockwise movement as viewed in FIGURE 21 by anadjustable eccentric stop 322. The plate 320 is provided with a hookportion 324 which is substantially concentric with the needle cylinderaxis. This permits reciprocations of the sinker cap during reciprocatoryknitting. The hook portion 324 is arranged to be engaged by theupstanding portion 326 of a bell crank 328 pivoted at 330 to a slide 332which is slidable in guides 334 mounted on a bracket 336. The spring 338urges the slide 332 to the left as viewed in FIGURE 22 toward a positionlimited by shoulders 340. A bell crank 342 pivoted at 344 to a bracketfastened to the latch ring support post 336 is operable from the maincam drum through a rod 346 and is provided with a pad 348 urgedoutwardly by a strong spring 350 capable of overcoming the tension ofspring 338. The link 98, previously described with reference to FIGURE17, is pivotally connected to bell crank 328 for operation thereof bythe piston rod 94.

In the operation involved in accordance with FIGURES 20, 21 and 22control is efiected by reason of the fact that the sinkers are variablypositioned by the cam 306 under the action of spring band 317 at thetime the stitches are drawn, the control resulting from the positioningof portions of the ledges at diflerent heights at the locations Wherethey are engaged by the yarn during stitch drawing. Numerous variationsmay be involved as, for example, when the stitches are beingcontrolledsolely from the main cam drum, by height adjustment of the needlecylinder, the automatic control is rendered inoperative in the fashionsdescribed above including the forcing upward of rod 346 which permitsthe sinkers to occupy their innermost position by release of the plate320. Under these conditions, if the sinker shown in FIGURE 20 is used,the stitches will be drawn in conventional fashion over the horizontalportion 301 of the ledge. When automatic control is to occur, slide 332is permitted to move to its extreme outer position, thereby moving thecam 306 into the range of positions wherein stitches will be drawn onlyon the sloping portion 364 of each sinker ledge, the needle cylinderbeing positioned so that, within the range of variations of engagementof ledge portion 300 by the yarn, stitches of proper size will beformed. The adjustment of cam 3% for automatic control of stitch size iseffected by the action of link 98 and bell crank 323, the link 98 beingoperated from the pneumatic cylinder 84 in response to the stitch sizedetecting means as described previously.

FIGURES 23 and 24 show mechanism for efiecting stitch control bychanging the position of the sinker cams with respect to the needleoperating cams in a circumferential direction.

A conventional sinker cap is indicated at 354 and is provided with theusual forward and reverse bumper screws 356 and 353 en-gageable with thebracket 36!). in accordance with the invention an additional bumperscrew 362 is provided. A bushing 365 has its shank 364 slidably mountedin an opening in the bracket 360 and is held against rotation byengagement of a screw 37%, acting as a key, within a slot 368 in thebushing shank. The bushing 365 is internally threaded for the receptionof a screw 372 the end of which is engageaole by the bumper screw 362.At its right hand end the screw 372 has ailixed thereto a pinion 374arranged to be rotated by a rack 3'6 which is guided for verticalmovements in the machine frame. A forked lever 373 engages the head ofthe bushing 366 and is pivoted at 380 for operation through a link 382connected to a cam following lever engageable by cams on the main camdrum. The rack 376 has its movements controlled from the pneumaticcylinder by the interconnecting link 98.

During periods when automatic control is not effected, the bushing 365is released by the lever 37S, and the bumper screw 356 is then effectiveto determine the position of the sinker cap during movement of theneedle cylinder in rundown direction either during rotary or durinreciprocatory knitting. It will be noted that the added mechanism doesnot interfere with the action of the screw 35% in locating the sinkercap during reverse reciprocations in reciprocatory knitting.

When automatic control is to be efiected, a cam on the main cam drumacting through link 382 forces the bushing 36% to its left-hand positionso that the screw 372 is projected for engagement with the screw 352. Ingeneral, the screw 372 will be in such position that when renderedoperative as just stated it will cause a counterclockwise movement ofthe sinker cap beyond the position determined by the normal bumper screw356. Rotation of the screw 372 by the rack 376 controls its axialposition thus adjusting the sinker cap position and, in particular, theposition of the sinker projecting cam to control the knock-over action.This affects the size of stitches in the same general fashion as wasinvolved in the operation of the modification involving FIGURE 13, withthe sole difference that the time of inward sinkers movement relative tothe needle Wave is controlled by circumferential displacement of a camsimilar to 254 rather than its radial displacement as shown in FIG- URE13.

Both loosening and tightening of stitches is possible through sinker cappositioning. If longer stitches are called for, the action is to movethe sinker cap in a direction to cause the sinkers to be cammed inwardlyslightly earlier and further than usual. Conversely, if sinker stitchesthat are too long are being formed, the operation is such that thesinker cap is moved so that the sinkers are moved outwardly to efiectformation of smaller sitches.

It has been found that such variable positioning of the sinker cap willcause loosening of a comparatively loose stitch as Well as a tightstitch, and accordingly, the control of this type is effective for fineadjustments of stitch size even though the major action in controllingstitch size is by reason of the relationship of the height of the needlecylinder with respect to the needle operating cams. Accordingly,determination of stitch size and fashioning may be carried out by heightchanges of the needle cylinder in generally conventional fashion, thecontrol of rack 376 then providing only corrective adjustments, thewedge 188 being, of course, adjusted to correspond to the size ofstitches being produced.

It will be evident from the foregoing that in accordance with theinvention control of stitch size and of length of stockings may beeffected in various ways, and it is therefore to be understood that theinvention is not to be regarded as limited except as required by thefollowing claims.

What is claimed is:

1. Stitch control means for a knitting machine having needles, sinkersand cam means for moving the sinkers transversely to the lengths of theneedles, comprising sensing means responsive to the size of stitchesproduced, and means responsive to said sensing means controllingmovements of said cam means, thereby to control the size of stitchesbeing formed.

2. Stitch control means for a knitting machine having needles, sinkers,and cam means for moving the sinkers transversely to the lengths of theneedles, comprising sensing means responsive to the size of stitchesproduced, and means responsive to said sensing means controlling thecastoff movements of the sinkers, thereby to control the size ofstitches being formed.

3. Stitch control means for a knitting machine having needles, sinkersand cam means for moving the sinkers transversely to the lengths of theneedles, comprising sensing means responsive to the size of stitchesproduced, and means controlling movements of said cam means, thereby tocontrol the size of stitches formed, the last-mentioned means comprisingpneumatic motor means and controlling means therefor operated by saidsensing means.

4. Stitch control means for a knitting machine having needles, sinkersand cam means for moving the sinkers transversely to the lengths of theneedles, comprising sensing means responsive to the size of stitchesproduced, pneumatic motor means controlling the castofif movements ofsaid cam means, thereby to control the size of stitches being formed,and controlling means for said pneumatic motor means comprising nozzleand bafile elements relatively movable by said sensing means.

5. Stitch control means for a knitting machine having needles, sinkershaving sloping ledges over which stitches may be drawn, and cam meansfor moving the sinkers transversely to the lengths of the needles,comprising sensing means responsive to the size of stitches produced,and means responsive to said sensing means controlling said cam means tomodify the sinker wave to change the relationship between the slopingsinker ledges and the needles during the drawing of stitches, thereby tocontrol the size of stitches being formed.

6. Stitch control means for a knitting machine having needles, sinkershaving sloping ledges over which stitches may be drawn, and cam meansfor moving the sinkers transversely to the lengths of the needles,comprising sensing means responsive to the size of stitches produced,and means for controlling said cam means to modify the sinker wave andchange the relationship between the sloping sinker ledges and theneedles during the drawing of stitches, thereby to control the size ofstitches being formed, the last-mentioned means comprising pneumaticmotor means and controlling means therefor operated by said sensingmeans.

7. Stitch control means for a knitting machine having needles, sinkershaving sloping ledges over which stitches may be drawn, and cam meansfor moving the sinkers transversely to the lengths of the needles,comprising sensing means responsive to the size of stitches produced,pneumatic motor means controlling said cam means to modify the sinkerwave and change the relationship between the sloping sinker ledges andthe needles during the drawing of stitches, thereby to control the sizeof stitches being formed, and controlling means for said pneumatic motormeanstcomprising nozzle and bafile elements relatively movable by saidsensing means.

8. Stitch control means for a knitting machine having needles, sinkers,and a sinker cap embodying cam means for moving the sinkers transverselyto the lengths of the needles, comprising sensing means responsive tothe size of stitches produced, and means responsive to said sensingmeans controlling the position of said sinker cap to modify the sinkerWave, thereby to control the size of stitches being formed.

9. Stitch control means for a knitting machine having needles, sinkers,and a sinker cap embodying cam means gfor moving the sinkerstransversely to the lengths of the needles, comprising sensing meansresponsive to the size of stitches produced, and means controlling theposition of said sinker cap to modify the sinker wave, thereby tocontrol the size of stitches being formed, the last-mentioned meanscomprising pneumatic motor means and controlling means therefor operatedby said sensing means.

10.v Stitch control means for a knitting machine having needles,sinkers, and a sinker cap embodying cam means l i for moving the sinkerstransversely to the lengths of the needles, comprising sensing meansresponsive to the size of stitches produced, pneumatic motor meanscontrolling the position of said sinker cap to modify the sinker Wave,thereby to control the size of stitches being formed, and controllingmeans for said pneumatic motor means comprising nozzle and baflieelements relatively movable by said sensing means.

References Cited by the Examiner UNITED STATES PATENTS 1,189,220 6/16Scott 66--55 2,056,686 10/36 Mills 66-108 X 2,197,706 4/40 Peloquin66-108 X 2,617,282 11/52 Reichert 6638 2,685,786 8/54 Stack 66-55FOREIGN PATENTS 807,292 6/57 Germany. 526,280 9/40 Great Britain.585,894 2/47 Great Britain.

RUSSELL C. MADER, Primary Examiner.

1. STITCH CONTROL MEANS FOR A KNITTING MACHINE HAVING NEEDLE, SINKERSAND CAMS MEANS FOR MOVING THE SINKERS TRANSVERSELY TO THE LENGTHS OF THENEEDLES, COMPRISING SENSING MEANS RESPONSIVE TO THE SIZE OF STITCHESPRODUCED, AND MEANS RESPONSIVE TO SAID SENSING MEANS CONTROLLING MOVE-